Weather Vane: Surplus evaporates in crucial July

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Nearly one-third of the season’s rain falls in this month

The rainfall surplus at the end of June has evaporated and the monsoon has dipped into the red with a big deficit of 51 per cent during the first week of July. This is in line with an India Met Department assessment that the crucial second month of the monsoon may fall short by 8 per cent. But the extent by which it has gone off the normal is unnerving. A full-scale revival of rains is ruled out at least until the last week of the month.

July and August are the most productive months of the monsoon. Nearly one-third of the rain for the season falls during July. The country receives almost 20 per cent more rains in July than August; about 40 per cent more than June; and 70 per cent more than September.

Crucial months

At least 21 out of 30 Met subdivisions surveyed (of 36 overall) receive the highest monthly rainfall in July. This ranges between a high of 40 per cent of seasonal rainfall in Saurashtra and 21 per cent in Tamil Nadu. July and August combine to contribute two-thirds of the seasonal rainfall in about 14 sub-divisions. Madhya Pradesh gets more than 70 per cent during this period.

The National Agromet Advisory Service Bulletin based on Extended Range Weather Forecast (valid for July 10 to 23) and issued by the India Met Department in association with the Indian Institute of Tropical Meteorology, Pune, and the Indian Council of Agriculture Research facility at Hyderabad, gives the following update:

During the last fortnight, good rainfall occurred mainly over Uttarakhand, Uttar Pradesh, Bihar, Jharkhand and West Bengal. The next fortnight will see rainfall confined to eastern and northern belt and the Gangetic Plains while it will be subdued in central India and the northwest. Increase of rainfall is likely over North-eastern States and parts of south peninsula. However, the western parts of central India, Rajasthan and western coastal states of India will remain mainly dry.

Forecast

The US Climate Prediction Centre too shares this outlook. And therein lies the rub. Rainfall has been mostly scanty over large parts of peninsular India, central India and adjoining west India. It is now left to the next visit of Madden-Julian Oscillation (MJO) wave that circumnavigates the globe to trigger a revival of the monsoon.

The wave is just about exiting the Pacific where its amplitude was at a historic high (the most since 1981) which was evidenced in the way it has set up typhoons (cyclones) one after the other in the Pacific.

It was during its earlier visit over the Indian Ocean in June that it helped the monsoon here drive to a peak. It is now expected to show up during the last week of July, if at all.

Below normal rainfall is forecast over the remaining parts of the country that covers most of the affected area in south, central and west India.

Progress in sowing

The total kharif-sown area as on July 10, 2015, as per reports received from states stands at 445.11 lakh hectare (ha) as compared to 275.10 lakh ha on the same day last year.

Significant increase has been recorded in oilseeds sowing this season; it has reached 101.26 lakh ha while last year on the day it was 22.24 lakh ha, an increase of 355 per cent. Similarly, pulses has touched 32.61 lakh ha this season, and cotton 87.83 lakh ha, almost double than the last year.

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